1. Field of the Invention
The present invention relates to a method for transmitting a packet in a packet-mode wireless access network, and more particularly to a method for transmitting a packet in a packet-mode wireless access network, which can guarantee a bandwidth by assigning a unique wavelength to each RNC (Radio Network Controller) in a packet-mode wireless access network, improve access network utilization and simplify packet transmission by transmitting/receiving the packet being identified by the unique wavelength, and provide high-speed paging and broadcasting services by commonly assigning a specific shared wavelength to all RNCs.
2. Description of the Related Art
Recently, as numbers of wireless Internet users and a demand of multimedia services increase, a need for large-capacity packet transmission services has increased. Further, a B-ISDN (Broadband Integrated Services Digital Network) is being rapidly developed to accommodate a variety of services such as e-mail services, e-commerce services, moving image services for Internet broadcasting, remote image conference services, home shopping services, on-line real-time game services, home networking services, etc. Therefore, it is important that wireless Internet services of more than several Mbits/s per mobile terminal subscriber should be supported for the sake of the large-capacity packet transmission in a wireless access network.
A conventional access network between a base station and a backbone network is based on a point-to-point connection structure through an ATM (Asynchronous Transfer Mode)/SDH (Synchronous Digital Hierarchy)/SONET (Synchronous Optical Network) interface. Further, a packet transmission process is complicated in the conventional access network and the capacity of the conventional access network cannot accommodate a fourth generation mobile communication system, which guarantees a bandwidth of more than several Mbits/s per mobile subscriber. The capacity of the backbone network is sufficient for a current wired network, but high-speed data services of large capacity cannot be provided to a mobile terminal subscriber because the capacity of the conventional access network is limited.
FIG. 1 is a view showing a GPRS (General Packet Radio Service) network architecture, which supports packet-mode services of up to several hundred Kbits/s being currently standardized in a 3GPP (Third Generation Partnership Project). The network architecture for only the packet-mode services is shown in FIG. 1, but the SMS (Short Message Service) and the CAMEL (Customized Application for Mobile network Enhanced Logic) as supplementary services are omitted from FIG. 1. Briefly describing components of the GPRS network architecture shown in FIG. 1, a MT (mobile terminal) 11 is a mobile terminal for the packet-mode services and a UTRAN (UTMS Terrestrial Radio Access Network) 12 is a wireless base-station access network in which a UMTS (Universal Mobile Telecommunications System) is employed. Actually, the UTRAN 12 is physically made up of a base station, an RNC (Radio Network Controller) and a connection link between the base station and the RNC. An SGSN (Serving GPRS Support Node) 13 is connected to a plurality of RNCs (not shown) and the SGSN 13 acts as a router for routing a packet between the RNC and a GGSN (Gateway GPRS Support Node) 14. Further, the SGSN 13 performs a mobility management function, a billing data creation function, etc. An interface between the RNCs is called “Iur” where signaling and data paths are directly connected. The “Iur” is used as a packet-forwarding path between a source RNC (an RNC to which a source mobile terminal belongs, before soft-handover is performed) and a target RNC (another RNC to which a destination mobile terminal belongs, after the soft-handover has been performed) when the soft-handover is performed.
The GGSN 14 acts as a router for interfacing with an external network (e.g., an IP (Internet Protocol) network) and a host of a mobile terminal within the GGSN 14. An HLR (Home Location Register)/VLR (Visitor Location Register) 15 manages subscriber information and location information of the mobile terminal. Further, the GGSN 14 is linked to a PDN (Public Data Network) 16 where TEs (Terminal Equipments) 17 are connected.
The GPRS, which is a mobile communication network service for supporting the packet-mode services to a mobile terminal, has been derived from a GSM (Global System for Mobile communications). Packetized data of a maximum 115 Kbits/s at the user terminal (e.g., IP packets) are transferred to a RNC via a radio bearer of a wireless section, then further transferred by the routing function of the RNC to destinations over wired packet networks. The GPRS is provided to the subscriber so that the subscriber transmits and receives data in a packet transfer mode between terminations without using network resources of a line-switching mode. However, the GPRS is complicated because it is made up of two stages. Further, a procedure of transmitting the packet in the GPRS is not efficient because a control signal and a data protocol stack are separated from each other (a reference document: 3GPP TS 23.060, “GPRS Service Description Stage 2”, October, 2001).
Korean patent application No. 2000-79533 discloses an IPOW (Internet Protocol Over WDM) architecture for routing/transmitting a packet over a DWDM (Dense Wavelength Division Multiplexing) optical communication network based on a wavelength identification code scheme, and constituent systems and methods for transmitting/receiving the packet in the IPOW architecture. However, there is a disadvantage in that the conventional systems and methods cannot fully solve the problem with packet transmission capability of a wireless access network in terms of core requirements of bandwidth and QoS (quality of service) for Internet services. Further, there is another disadvantage in that the conventional systems and methods have been posed a complexity in implementing high-speed mobility services.